accumulator

package
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Published: Mar 11, 2022 License: Apache-2.0 Imports: 6 Imported by: 0

Documentation

Overview

Package accumulator implements the cryptographic accumulator as described in https://eprint.iacr.org/2020/777.pdf It also implements the zero knowledge proof of knowledge protocol described in section 7 of the paper. Note: the paper only describes for non-membership witness case, but we don't use non-membership witness. We only implement the membership witness case.

Index

Constants

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Variables

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Functions

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Types

type Accumulator

type Accumulator struct {
	// contains filtered or unexported fields
}

Accumulator is a point

func (*Accumulator) Add

func (acc *Accumulator) Add(key *SecretKey, e Element) (*Accumulator, error)

Add accumulates a single element into the accumulator V' = (y + alpha) * V

func (*Accumulator) AddElements

func (acc *Accumulator) AddElements(key *SecretKey, m []Element) (*Accumulator, error)

AddElements accumulates a set of elements into the accumulator.

func (Accumulator) MarshalBinary

func (acc Accumulator) MarshalBinary() ([]byte, error)

MarshalBinary converts Accumulator to bytes

func (*Accumulator) New

func (acc *Accumulator) New(curve *curves.PairingCurve) (*Accumulator, error)

New creates a new accumulator.

func (*Accumulator) Remove

func (acc *Accumulator) Remove(key *SecretKey, e Element) (*Accumulator, error)

Remove removes a single element from accumulator if it exists V' = 1/(y+alpha) * V

func (*Accumulator) UnmarshalBinary

func (acc *Accumulator) UnmarshalBinary(data []byte) error

UnmarshalBinary sets Accumulator from bytes

func (*Accumulator) Update

func (acc *Accumulator) Update(key *SecretKey, additions []Element, deletions []Element) (*Accumulator, []Coefficient, error)

Update performs a batch addition and deletion as described on page 7, section 3 in https://eprint.iacr.org/2020/777.pdf

func (*Accumulator) WithElements

func (acc *Accumulator) WithElements(curve *curves.PairingCurve, key *SecretKey, m []Element) (*Accumulator, error)

WithElements initializes a new accumulator prefilled with entries Each member is assumed to be hashed V = prod(y + α) * V0, for all y∈ Y_V

type Coefficient

type Coefficient curves.Point

Coefficient is a point

type Delta

type Delta struct {
	// contains filtered or unexported fields
}

Delta contains values d and p, where d should be the division dA(y)/dD(y) on some value y p should be equal to 1/dD * <Gamma_y, Omega>

func (*Delta) MarshalBinary

func (d *Delta) MarshalBinary() ([]byte, error)

MarshalBinary converts Delta into bytes

func (*Delta) UnmarshalBinary

func (d *Delta) UnmarshalBinary(data []byte) error

UnmarshalBinary converts data into Delta

type Element

type Element curves.Scalar

type MembershipProof

type MembershipProof struct {
	// contains filtered or unexported fields
}

MembershipProof contains values in the proof to be verified

func (*MembershipProof) Finalize

func (mp *MembershipProof) Finalize(acc *Accumulator, pp *ProofParams, pk *PublicKey, challenge curves.Scalar) *MembershipProofFinal

Finalize computes values in the proof to be verified.

func (MembershipProof) MarshalBinary

func (mp MembershipProof) MarshalBinary() ([]byte, error)

MarshalBinary converts MembershipProof to bytes

func (*MembershipProof) UnmarshalBinary

func (mp *MembershipProof) UnmarshalBinary(data []byte) error

UnmarshalBinary converts bytes to MembershipProof

type MembershipProofCommitting

type MembershipProofCommitting struct {
	// contains filtered or unexported fields
}

MembershipProofCommitting contains value computed in Proof of knowledge and Blinding phases as described in section 7 of https://eprint.iacr.org/2020/777.pdf

func (*MembershipProofCommitting) GenProof

GenProof computes the s values for Fiat-Shamir and return the actual proof to be sent to the verifier given the challenge c.

func (MembershipProofCommitting) GetChallengeBytes

func (mpc MembershipProofCommitting) GetChallengeBytes() []byte

GetChallenge returns bytes that need to be hashed for generating challenge. V || Ec || T_sigma || T_rho || R_E || R_sigma || R_rho || R_delta_sigma || R_delta_rho

func (*MembershipProofCommitting) New

New initiates values of MembershipProofCommitting

type MembershipProofFinal

type MembershipProofFinal struct {
	// contains filtered or unexported fields
}

MembershipProofFinal contains values that are input to Fiat-Shamir Heuristic

func (MembershipProofFinal) GetChallenge

func (m MembershipProofFinal) GetChallenge(curve *curves.PairingCurve) curves.Scalar

GetChallenge computes Fiat-Shamir Heuristic taking input values of MembershipProofFinal

type MembershipWitness

type MembershipWitness struct {
	// contains filtered or unexported fields
}

MembershipWitness contains the witness c and the value y respect to the accumulator state.

func (*MembershipWitness) ApplyDelta

func (mw *MembershipWitness) ApplyDelta(delta *Delta) (*MembershipWitness, error)

ApplyDelta returns C' = dA(y)/dD(y)*C + 1/dD(y) * <Gamma_y, Omega> according to the witness update protocol described in section 4 of https://eprint.iacr.org/2020/777.pdf

func (*MembershipWitness) BatchUpdate

func (mw *MembershipWitness) BatchUpdate(additions []Element, deletions []Element, coefficients []Coefficient) (*MembershipWitness, error)

BatchUpdate performs batch update as described in section 4

func (MembershipWitness) MarshalBinary

func (mw MembershipWitness) MarshalBinary() ([]byte, error)

MarshalBinary converts a membership witness to bytes

func (*MembershipWitness) MultiBatchUpdate

func (mw *MembershipWitness) MultiBatchUpdate(A [][]Element, D [][]Element, C [][]Coefficient) (*MembershipWitness, error)

MultiBatchUpdate performs multi-batch update using epoch as described in section 4.2

func (*MembershipWitness) New

New creates a new membership witness

func (*MembershipWitness) UnmarshalBinary

func (mw *MembershipWitness) UnmarshalBinary(data []byte) error

UnmarshalBinary converts bytes into MembershipWitness

func (MembershipWitness) Verify

func (mw MembershipWitness) Verify(pk *PublicKey, acc *Accumulator) error

Verify the MembershipWitness mw is a valid witness as per section 4 in <https://eprint.iacr.org/2020/777>

type ProofParams

type ProofParams struct {
	// contains filtered or unexported fields
}

ProofParams contains four distinct public generators of G1 - X, Y, Z

func (*ProofParams) MarshalBinary

func (p *ProofParams) MarshalBinary() ([]byte, error)

MarshalBinary converts ProofParams to bytes

func (*ProofParams) New

func (p *ProofParams) New(curve *curves.PairingCurve, pk *PublicKey, entropy []byte) (*ProofParams, error)

New samples X, Y, Z, K

func (*ProofParams) UnmarshalBinary

func (p *ProofParams) UnmarshalBinary(data []byte) error

UnmarshalBinary converts bytes to ProofParams

type PublicKey

type PublicKey struct {
	// contains filtered or unexported fields
}

PublicKey is the public key of accumulator, it should be sk * generator of G2

func (PublicKey) MarshalBinary

func (pk PublicKey) MarshalBinary() ([]byte, error)

MarshalBinary converts PublicKey to bytes

func (*PublicKey) UnmarshalBinary

func (pk *PublicKey) UnmarshalBinary(data []byte) error

UnmarshalBinary sets PublicKey from bytes

type SecretKey

type SecretKey struct {
	// contains filtered or unexported fields
}

SecretKey is the secret alpha only held by the accumulator manager.

func (SecretKey) BatchAdditions

func (sk SecretKey) BatchAdditions(additions []Element) (Element, error)

BatchAdditions computes product(y + sk) for y in additions and output the product

func (SecretKey) BatchDeletions

func (sk SecretKey) BatchDeletions(deletions []Element) (Element, error)

BatchDeletions computes 1/product(y + sk) for y in deletions and output it

func (SecretKey) CreateCoefficients

func (sk SecretKey) CreateCoefficients(additions []Element, deletions []Element) ([]Element, error)

CreateCoefficients creates the Batch Polynomial coefficients See page 7 of https://eprint.iacr.org/2020/777.pdf

func (SecretKey) GetPublicKey

func (sk SecretKey) GetPublicKey(curve *curves.PairingCurve) (*PublicKey, error)

GetPublicKey creates a public key from SecretKey sk

func (SecretKey) MarshalBinary

func (sk SecretKey) MarshalBinary() ([]byte, error)

MarshalBinary converts SecretKey to bytes

func (*SecretKey) New

func (sk *SecretKey) New(curve *curves.PairingCurve, seed []byte) (*SecretKey, error)

New creates a new secret key from the seed.

func (*SecretKey) UnmarshalBinary

func (sk *SecretKey) UnmarshalBinary(data []byte) error

UnmarshalBinary sets SecretKey from bytes

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